An unusually large propeller feature is detected just beyond the Encke Gap in this Cassini image of Saturn's outer A ring taken a couple days after the planet's August 2009 equinox. Image Credit: NASA/JPL/Space Science Institute

This movie created from images obtained by NASA's Cassini spacecraft shows a propeller-shaped structure created by a hidden, embedded moon moving through one of Saturn's rings. Image Credit: NASA/JPL/SSI